<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/4.1.1/animate.min.css" />
</head>
<style>
    
</style>

<body>
    <button onclick="fun()">点击</button>
    <div class=""></div>
    <h1 class="animate__animated animate__bounce" id="box">An animated element</h1>
</body>
<script>
    function fun() {
        var box = document.getElementById("box");
    }
</script>

</html>